Aluminum container for hydrogen peroxide



Patented Oct. 29, 1940 ALUMINUM CONTAINER FOR HYDROGEN PER-OXIDE Max E.Bretschger, Buffalo, Hans 0. Kaufimann,

Eg'gertsville, and Frederick A. Gilbert, Buffalo,

- N. Y., assignors to Buffalo Electra-Chemical Company, Inc., Buffalo,N. Y.

No Drawing. Original application July 13, 1936, Serial No. 90,440.Divided and this application February 23, 1940, Serial No. 320,434

2 Claims. (01. 23 240) This invention relates to metallic containers forhydrogen peroxide solutions and more particularly to aluminum containerstreated to withstand attack by hydrogen peroxide.

This is a division of our co-pending application Serial No. 90,440,filed July 13, 1936.

Repeated statements are found in the literature that hydrogen peroxideattacks metallic aluminum, with the formation of pits and holes, andattempts to use hydrogen peroxide in contact with metallic aluminumcontainers heretofore have been unsuccessful unless the surface of thealuminum container, in contact with the peroxide, had been given aprotective treatment.

Suggestions have been made heretofore to coat the interior of metallicaluminum containers, used for transportation or storage of hydrogenperoxide, either with certain mixtures of paraffin and petrolatum or thelike, or to coat the metallic aluminum with an artificial film of oxideby oxidizing the interior surface of the container with nitric acid asan oxidizing acid.

In accordance with the present invention and contrary to the priorteachings, metallic aluminum is used for storage vessels of hydrogenperoxide. However, the surface of the aluminum container is cleaned oretched with a non-oxidizing acid, that is, one which reacts withmetallic aluminum without decomposition of its anion, probably removingthe adhering oxide film, so that the aluminum metal is exposed tocontact with the hydrogen peroxide therein. Thus, an aluminum container,such as an aluminum drum used for transportation of hydrogen peroxide,is filled with sulfuric acid at room temperature and permitted to standfor about one .to two hours, the sulfuric acid removed and the drumrinsed with Water. The sulfuric acid may be brushed or sprayed upon theinterior surface of the con tainer or a small amount placed in thecontainer and agitated therein until the desired contact is obtained.This treatment probably removes the tightly adhering aluminum oxide andleaves a fresh surface of aluminum. Where the drum is not initiallyclean, it should be washed well with soap and water or with lye orcaustic soda solution to remove grease, etc., and well rinsed with Waterprior to the surface etching with the nonoxidizing acid. In some casesit may be found advantageous toclean the metal surfiace initially withorganic solvents, such as carbon tetrachloride, naphtha and the like.

Sulfuric acid is an excellent non-oxidizing acid for producing an etchon the interior of an aluminum container. In general, the etch can [befinished with any suitable concentration of acid, and the time ofcontact need not be great, a good etch being obtained within a halfhour.

Thus a strip of aluminum was etched for 1 hours in 50% aqueous sulfuricacid and immersed in 100 volume hydrogen peroxide. After five daysimmersion the strip showed no signs of pitting.

The surface of the aluminum vessel, after being treated with thenon-oxidizing acid, to induce the protective efiector inhibiting action,possesses a dulled and etched appearance Without the sheen or polishpossessed by the untreated metallic aluminum. Commercial hydrogen:peroxide solutions in contact with aluminum surfaces not [treated inaccordance with the present invention react therewith and pit the samewith the formation of a white flocculent material adhering to thealuminum metal and dispersed in the peroxide solution. This actioncontinues and the metal is finally eaten through.

After contact with the hydrogen peroxide solution, the interior of thetreated aluminum vessel is generally darkened, appearing brown to black,in direct light and showing interference colors in reflected lightindicating the presence upon the metal of a film of deposited materialin a fine state of subdivision.

After use, the vessel needs no further or additional treatment with thenon-oxidizing acid as the surface, once treated with the non-oxidizingacid, acquires, after use, a passivity or inactivity towards hydrogenperoxide solutions, permitting repeated use in contact with peroxide,although if the surface be marred or scratched, the area should be againtreated.

The term non-oxidizing acid as used in the claims designates an acid thehydrogen of which is liberated as gaseous hydrogen when the acid actsupon metallic aluminum.

From the foregoing it will .be seen that the present invention providesa method of treating metallic aluminum vessels whereby the saline can beused with safety in contact with hydrogen peroxide solutions without thedestruction of the vessel and without adversely affecting the stabilityof the hydrogen peroxide.

What is claimed is.

1. The method of packaging hydrogen peroxide which comprises treatingthe interior surface of an aluminum vessel with sulfuric acid to etchthe same and thereafter placing hydrogen peroxide in said vessel incontact with the surface so treated.

2. A package comprising a container havingan MAX E. BRETSCHGER. HANS O.KAUFFMANN. FREDERICK A. GILBERT.

